There are a great many engineering applications that require an expander or compressor capable of handling a two phase flow of liquid and vapor. For example, two phase expanders improve the efficiency of geothermal power plants. Also, if a two phase expander were to replace the throttling valve of a refrigerator or an air conditioner, the coefficient of performance of these devices could be improved by approximately 25%. Their performance could be even further improved if a two phase compressor could be developed. In considering the above-described applications, one with skill in this art would conclude that for such a two phase device to be of use, it would have to be capable of utilizing a very high expansion ratio or of producing a very high compression ratio. It also would have a high adiabatic efficiency.
U.S. Pat. No. 2,990,109, issued Jun. 27, 1964, to G. D. Fraser describes the basic concepts which are improved upon by the present invention. The Fraser patent describes a double acting rotary compressor having an elliptic stator, and elliptic chamber, and a hollow tubular rotor which Fraser described as follows: "The tubular rotor has plurality of equally spaced vane slots containing vanes which are slidable in said slots and make contact at all times with the elliptical surface of the stator and the elliptical wall of the casing chamber." Fraser specified that the rotor would be in contact with the inner elliptical stator at both ends of the major axis of the ellipse while contacting the outer elliptical stator chamber at the ends of the minor axis in order to produce his desired result. As Fraser states: "The result of this construction is that two diametrically opposed crescent-shaped chambers are formed between the outer tubular surface of the rotor and the elliptical wall of the casing chamber, forming one compressor stage; and two diametrically opposed crescent-shaped chambers are formed between the elliptical surface of the stator and the inner tubular surface of the rotor, constituting the second compressor stage." Fraser also specified a certain design for the vanes and that the intake and discharge passages be part of the cover plate. As stated by Fraser: "Additional novel features of the invention, hereinafter more fully described, include the construction and arrangement of the vanes carried by the rotor, and the various combination of elements including in particular the intake and discharge passages in the cover plate cooperating with the different compressor chambers."
It is an object of the present invention to provide a two stage rotating vane apparatus which can be used as pump, compressor, expander, gas turbine engine, a refrigerator or air conditioner, or a turbo-supercharger for internal combustion engines.
It is further object of the present invention to provide a two stage rotating vane apparatus in which the tubular rotor does not contact either stator.
It is a still further object of the present invention to provide a two stage rotating vane apparatus in which intake and discharge ports are located on the walls of the stator at the appropriate angles for a desired application of the invention.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.